Computed tomography (CT) is an X-ray imaging modality that providing the ability to non-invasively gain information about three-dimensional structure within an object. While computed tomography has been pervasive in medical, diagnostic, and intraoperative applications since its development in 1972, it has also been tailored to industrial applications mostly since the 1990's. Industrial metrology systems are described, for example, in U.S. Pat. Nos. 5,027,378 and 4,422,177.
Industrial computed tomography systems, e.g., such as coordinate measuring machines (CMM), can allow objects and work pieces, which may have external and internal structure made of metal, plastics, composites, and other materials, to be investigated without disassembly or destruction. Non-destructive measurement or investigation can be particularly useful in a final stage of industrial manufacturing, where a work piece may require validation of precise dimensions and internal construction. This capability can also be useful for later stage analysis, such as failure prediction or analysis.
To allow precise measurements of a work piece or detection of fine defects, such as cracks, vacancies, or similar features, industrial CT systems may utilize microfocus X-ray sources for their ability to provide micron-level resolution. Microfocus X-ray tubes can be relatively limited in operating power relative to sources having larger focal spots due to the enhanced localization of the thermal load in the anode. Potentially high densities or large sizes of work pieces in conjunction with relatively lower X-ray tube power can cause scan times in industrial metrology to be significantly longer than for medical CT scans. Overly long scan times can limit throughput of a manufacturing operation.
Computed tomography systems have also been tailored for dental imaging applications in recent years. Dental computed tomography images can provide information including the structure and density of teeth and jaw bones and the positioning of nerves. This information can be useful for various types of surgical planning as well as improving the ability to complete a pre-surgical assessment of whether a patient is a good candidate for dental implants.
The utility of computed tomography images in metrology, dental, and other applications can be dependent not only on image resolution but also on image quality aspects such as the contrast-to-noise ratio (CNR) of the image, presence of artifacts that obscure image details, or other aspects that affect the ability to resolve true internal features of the imaging subject. These aspects of image quality can be determined by a variety of factors, including the X-ray tube power and total scan time. What is needed is a system and method of providing high image quality within scan time and tube power constraints of a CT application.